1. Field of the Invention
The present invention generally relates to printers. More particularly, the present invention relates to the ink supply and delivery systems of printer cartridges for ink jet printers.
2. Description of the Related Art
Ink jet printers have historically placed the ink supply and the nozzle array in a single, disposable cartridge, which is inserted into the printer. While the design is simple, this arrangement results in a relatively high cost per printed page and shortens user intervention intervals as the cartridge must be frequently replaced. Moreover, these problems are particularly acute in ink jet printers that are used in network environments where the printer must be designed with greater ink capacities to lower the cost per page and lengthen the user intervention interval.
The placement of large quantities of ink on the moving printer cartridge carrier is not practical due to the excessive mass that has to be accelerated and controlled as the carrier traverses the media being printed upon. One typical solution to this problem is to provide stationary ink tanks mounted in the machine and then transport the ink through a fluid connection to the print head when needed for printing. The ink transport is thus typically accomplished by tubes connected between the ink tanks and the print head. Alternatively, some printers use a "dock and fill" approach in which the print head "docks" with the ink tanks and ink is transferred to "fill" the printer cartridge for use in printing.
With either of the above ink delivery systems, the provision of a controlled pressure to the ink is necessary in order to achieve the desired ink transfer in a reasonable time. Various techniques have therefore been used to pressurize the ink in the tanks to induce flow of the ink, but the known systems tend to be complex, costly, not independent of orientation, and do not provide constant pressure to the ink over the life of the printer. Therefore, an improved ink supply and delivery system for the printer cartridge that addresses and solves these problems would be advantageous. Accordingly, it is to the provision of such an improved ink supply and